Double crack growth analysis in the presence of a bi-material interface using XFEM and FEM modelling

• XFEM and FEM methods are used to analyse the interaction effect between two cracks.
• KI increases with increasing the distance h between two cracks up to h = 0.13 mm.
• KII was symmetric about the x-axis, decreased in absolute terms with increasing h.
• A divergence of the crack path was noted whose magnitude varies with distance h.

Standard and extended finite element methods are used to analyse the interaction effect between two cracks and elucidate the parameters that govern the growth and the path of these cracks in a mono-material. The same investigation is then generalised to a galvanised zinc/Trip steel 800 bi-material. The obtained results are afterwards compared to a bi-material with a softer substrate to check the effect of the substrate rigidity on the crack behaviour. The crack length and the distance between the two cracks are found to have a substantial influence on the crack path divergence. In addition, it is found that the more the substrate is stiff the more the cracks move away from each other.